As stated in introduction, a major evolutionary novelty in the brain of craniates is the presence of a forebrain, including a true telencephalon and a diencephalon.
The mineralized skeleton is a major evolutionary novelty that has contributed to the impressive morphological diversifications of the vertebrates.
As we accumulate evidence that whole genome duplications and interspecific hybridization play major roles in evolutionary novelties, the postulated epigenetic conflicts present a new and unexpected place to focus research on molecular control of evolution.
Duplications at different levels of organismal organization (e.g., gene network, cell type, tissue, body segment, behavioral program) are considered major sources of evolutionary novelties (West-Eberhard 2003).
The large number of genes per family suggests that the newly arisen gene duplicates are potentially major contributors to evolutionary novelties [ 4– 7].
Gene duplication is thought to be a major source of molecular evolutionary novelties (Ohno 1970).
Moreover, through functional differentiation of duplicates, tandem duplication is clearly a major source – perhaps the major source – of evolutionary novelty [ 55].
SCALEs enables the direct assessment of increased dosage effects on cellular phenotypes, which, while not encompassing all possible mutations, has been shown to represent a major source of evolutionary novelty in nature and to mimic many effects (i.e. gene overexpression, altered regulation, etc).
Despite gene duplication representing an analytical challenge for GBS, it is also a major source of evolutionary novelty (Ohno 1970; Lewis 1951).
In the past 40 years, there has been increasing acceptance that variation in levels of gene expression represents a major source of evolutionary novelty.
